Is HDR "Free" for the Xenos?

[Titanio]

I don't understand why some of you have issue with the notion of AA being "Free" for the Xenos.

Obviously "free" doesn't mean that it's done magically and without transistors. "Free" obviously means that it can be done without affecting system performance.

The issue is - it has no impact on performance as it is now, but where would performance have been if they hadn't invested Xm transistors in that feature?

No one's saying it's having an impact on Xenos performance as we know it now, but might wonder what could have been for shader performance if they'd spent more transistors there, for example (i.e. could have been even better).

It's a small matter, really, but I think referring to it as being "hardcoded" or "built-in" is a little more accurate.

 

[scooby_dooby]

Or do we know for sure the unified shader appraoch will not be a match for the the 24 shader pipelines in the RSX?

If this is in respones to my crude summing (and it is crude), I'm talking system architecture, not just GPUs. PS3 has more of stuff - more processors, more FLOPS, more BW between components, whereas XB360 has more stuff-saving features so it doesn't need as much stuff, like not needing as much BW as a high demand of BW is shipped to the eDRAM.

Regards shader performance it's still unknown. Without real-world Xenos measurements and RSX insight ti'll remain that way.

It's more in response to the general perpeption that I've been picking up that the RSX will offer more raw power, and the Xenos is more "efficient", many have described RSX as a pixel shading monster.

I was just trying to clarify if we actually do know which GPU is more powerful as far as pixel shading.

I think we don't, at this point, but most people are assuming that since the G70 has an extra 100million transistors to dedicate to shaders that it should in theory be more powerful.

It will be very interesting to see how the Xenos unified shaders compare to a 24/8 traditional approach.

 

[Tap In]

.... I'm inclined to write a summary of the system overviews as I think people have lost sight of the systems amongst specific numbers and sound bites. .....

please do




Great post Acret93

 

[BenQ]

I don't understand why some of you have issue with the notion of AA being "Free" for the Xenos.

Obviously "free" doesn't mean that it's done magically and without transistors. "Free" obviously means that it can be done without affecting system performance.

The issue is - it has no impact on performance as it is now, but where would performance have been if they hadn't invested Xm transistors in that feature?

No one's saying it's having an impact on Xenos performance as we know it now, but might wonder what could have been for shader performance if they'd spent more transistors there, for example (i.e. could have been even better).

It's a small matter, really, but I think referring to it as being "hardcoded" or "built-in" is a little more accurate.

I believe that argument is about as fair as if I were to ponder how much better the RSX could have been if Sony hadn't spent so much of it's transistor budget on all those SPE's. I could have had 3 SPE's instead of 7, and then maybe the RSX's shaders would be so powerful that we wouldn't have to be talking about the SPE's helping out the RSX, because the RSX could have been so much more powerful that it wouldn't need that help anyways.

..... rediculious.

 

[therealskywolf]

I don't understand why some of you have issue with the notion of AA being "Free" for the Xenos.

Obviously "free" doesn't mean that it's done magically and without transistors. "Free" obviously means that it can be done without affecting system performance.

The issue is - it has no impact on performance as it is now, but where would performance have been if they hadn't invested Xm transistors in that feature?

No one's saying it's having an impact on Xenos performance as we know it now, but might wonder what could have been for shader performance if they'd spent more transistors there, for example (i.e. could have been even better).

It's a small matter, really, but I think referring to it as being "hardcoded" or "built-in" is a little more accurate.

I think its a normal ammount of transistors, wich had more transistors? Fx 5900 or Ati Radeon 9800 pro? X850 or 6800?

I think the difference in transistors count in the RSx vs Xenos is the same as 6800 vs X850

Edit: Go no further, i have some numbers - X800 Xl 512 MB = 160 million Trans / Geforce 6800 GT = 220 Million+ Trans

Thats a 80+ million difference.

 

[London Geezer]

I believe that argument is about as fair as if I were to ponder how much better the RSX could have been if Sony hadn't spent so much of it's transistor budget on all those SPE's. I could have had 3 SPE's instead of 7, and then maybe the RSX's shaders would be so powerful that we wouldn't have to be talking about the SPE's helping out the RSX, because the RSX could have been so much more powerful that it wouldn't need that help anyways.

..... rediculious.

Huh?? The SPEs transistor count have nothing to do with RSX transistor count.

The RSX is as powerful and as packed with transistors as Sony can afford for the platform. Cutting transistors from Cell wouldn't make the RSX any better, since it would be tough to pack any more transistors in RSX and have good yields.

Titanio's post was completely justified and had nothing to resemble that kind of nonsense you posted.

 

[BenQ]

I believe that argument is about as fair as if I were to ponder how much better the RSX could have been if Sony hadn't spent so much of it's transistor budget on all those SPE's. I could have had 3 SPE's instead of 7, and then maybe the RSX's shaders would be so powerful that we wouldn't have to be talking about the SPE's helping out the RSX, because the RSX could have been so much more powerful that it wouldn't need that help anyways.

..... rediculious.

Huh?? The SPEs transistor count have nothing to do with RSX transistor count.

The RSX is as powerful and as packed with transistors as Sony can afford for the platform. Cutting transistors from Cell wouldn't make the RSX any better, since it would be tough to pack any more transistors in RSX and have good yields.

Titanio's post was completely justified and had nothing to resemble that kind of nonsense you posted.

I disagree. Transistors are transistors, and it's Sony who is manufacturing both the Cell and the RSX. The overal price of the PS3 has to be accounted for, and a Cell comprised of fewer transistors would simply cost less. A savings that could have been used to increas the RSX's transistor budget.

 

[scooby_dooby]

The point is this same argument can be made for any feature.

Well if you hadn't if done X you could've done more of Y.

It completely ignores the fact these are BALANCED systems and it's not nearly as simple as all that. The EDRAM is an integral part of the entire GPU design, everything in the GPU is built around the fact that the EDRAM is present.

Anyways I think this argument is extremely old, and especially considering no-one even knows for a fact that the RSX IS more powerful at pixel shading it's makes the entire argument useless.

What if the Xenos unified shader array ends up outperforming the RSX? The Xenos would have more shading power AND free AA+HDR. That sort of puts a whole new spin on the wasted transistors argument doesn't it?

 

[London Geezer]

I disagree. Transistors are transistors, and it's Sony who is manufacturing both the Cell and the RSX. The overal price of the PS3 has to be accounted for, and a Cell comprised of fewer transistors would simply cost less. A savings that could have been used to increas the RSX's transistor budget.

Look, you believe what u want to believe, but one can't just go "let me take 100M trannies out of Cell and put them on RSX!!!"...

Both chips would have to undergo massive architectural redisigns, and ultimately an RSX with 400M trannies would be very hard to get right, at good yields.

So, no, the 2 posts were not comparable. One was perfectly acceptable, the other wasn't, as Titanio was talking about changing the function and layout of transistors in a GPU for AA and use them for something else, on the same chip, and you are talking about taking transistors out of a chip, put them in another chip, stir well, serve hot and you have a better architecture.

 

[scooby_dooby]

So, no, the 2 posts were not comparable. One was perfectly acceptable, the other wasn't, as Titanio was talking about changing the function and layout of transistors in a GPU for AA and use them for something else, on the same chip, and you are talking about taking transistors out of a chip, put them in another chip, stir well, serve hot and you have a better architecture.

His example was just that, an example, The argument you guys are making coud be made pretty much every single feature in the entire system. It's basically 2nd guessing a design that hasn't even been benchmarked.

Lets wait till the performance numbers of the Xenos shaders before making claims that they wasted trannies. Without knowing the potential power provided, how can you even begin to speculate whether there was a need for more?

Perhaps Pixel Shading is one of the largest strengths of this GPU and the last thing they needed was "more"?

I mean it's a balanced system, with new technolgies, until we can actually benchmark it and see where it's weaknesses are, there's no point on speculating how or where they should've increased performance. We have no clue how the 48 unified shaders will perform compared to the 24/8 pipelines in the RSX.

 

[BenQ]

I disagree. Transistors are transistors, and it's Sony who is manufacturing both the Cell and the RSX. The overal price of the PS3 has to be accounted for, and a Cell comprised of fewer transistors would simply cost less. A savings that could have been used to increas the RSX's transistor budget.

Look, you believe what u want to believe, but one can't just go "let me take 100M trannies out of Cell and put them on RSX!!!"...

Both chips would have to undergo massive architectural redisigns, and ultimately an RSX with 400M trannies would be very hard to get right, at good yields.

So, no, the 2 posts were not comparable. One was perfectly acceptable, the other wasn't, as Titanio was talking about changing the function and layout of transistors in a GPU for AA and use them for something else, on the same chip, and you are talking about taking transistors out of a chip, put them in another chip, stir well, serve hot and you have a better architecture.

I think BOTH arguments are rediculious

How is it resonable to argue that it would have been better to use the transistor budget for more shaders rather than on another feature ( eDRAM ) designed specifically to remove certian bottlenecks found in every other GPUs shader core, and allow THOSE shaders to perform their tasks unhindered?!?!

The only way I could see an argument of that sort make sense would be if transisters were ACTUALLY wasted. For example, is the RSX shipped in the PS3 with all the G70's Pure video features.... now THAT would be a waste of transistoer that could have been CLEARLY better spent elsewhere.

Once again, I think BOTH arguments are rediculious.

 

[gurgi]

Look, you believe what u want to believe, but one can't just go "let me take 100M trannies out of Cell and put them on RSX!!!"...

I think that was the entire point. The daughter die is a seperate die, the SPEs are seperate. Saying you can just shift things around like that is silly. "Maybe RSX could be more powerful with SPE transistors"! It's all worthless fanboy drivel imo, and it is hilarious that this argument arose after a very well thought out post laying out how *ridiculous* the argument is in the first place.

 

[BenQ]

Look, you believe what u want to believe, but one can't just go "let me take 100M trannies out of Cell and put them on RSX!!!"...

I think that was the entire point. The daughter die is a seperate die, the SPEs are seperate. Saying you can just shift things around like that is silly. "Maybe RSX could be more powerful with SPE transistors"! It's all worthless <bleep> drivel imo, and it is hilarious that this argument arose after a very well thought out post laying out how *ridiculous* the argument is in the first place.

Exactly. = )

.... and stop making fun of my spelling = P

 

[Jawed]

[I believe that argument is about as fair as if I were to ponder how much better the RSX could have been if Sony hadn't spent so much of it's transistor budget on all those SPE's. I could have had 3 SPE's instead of 7, and then maybe the RSX's shaders would be so powerful that we wouldn't have to be talking about the SPE's helping out the RSX, because the RSX could have been so much more powerful that it wouldn't need that help anyways.

..... rediculious.

Precisely. With only 3SPEs, Sony could have put 2xRSX in SLI inside PS3 for the same overall cost and got way way more powerful graphics.

Actually, this crap PS3 design compromise deserves its own thread.

Jawed

 

[gurgi]

Look, you believe what u want to believe, but one can't just go "let me take 100M trannies out of Cell and put them on RSX!!!"...

I think that was the entire point. The daughter die is a seperate die, the SPEs are seperate. Saying you can just shift things around like that is silly. "Maybe RSX could be more powerful with SPE transistors"! It's all worthless <bleep> drivel imo, and it is hilarious that this argument arose after a very well thought out post laying out how *ridiculous* the argument is in the first place.

Exactly. = )

.... and stop making fun of my spelling = P

Heh, I honestly wasn't...just placing emphasis. I am in no position to be poking fun at anything to do with the english language. And yes, it is my first and only language. =P

 

[Titanio]

Here's a question:

Does anyone really think Xenos would be exactly as it was today if the daughter die wasn't there?

Edit: Go no further, i have some numbers - X800 Xl 512 MB = 160 million Trans / Geforce 6800 GT = 220 Million+ Trans

Thats a 80+ million difference. Wink

They're quite different chips. The one with the larger transistor count is implementing SM3.0 vs SM2.0 for starters.

I'm not comparing Xenos to RSX here at all by the way. I'm wondering what Xenos might have been like if the money spent on the daughter die was spent on Xenos. I'm not saying it would have emerged better or worse overall, but without knowing I prefer "built-in" to "free". That's all, relax.

 

[Jawed]

I'm still wondering why PS3 doesn't have 2x RSXs in SLI.

I wonder if the SLI circuitry is still there in RSX, wasting transistors?

Jawed

 

[Edge]

> "We have no clue how the 48 unified shaders will perform compared to the 24/8 pipelines in the RSX."

Would it not be more accurate to compare number of execution units, as each RSX pixel pipeline has dual shader units?

Would not saying Xbox360's GPU 48 unified shaders versus RSX's 48 pixel shaders/8 vertex shaders be more accurate?

> "I'm still wondering why PS3 doesn't have 2x RSXs in SLI."

Obviously cost, and heat output.

 

[overclocked]

I'm still wondering why PS3 doesn't have 2x RSXs in SLI.

I wonder if the SLI circuitry is still there in RSX, wasting transistors?

Jawed

Do you really think they could be used for something else, and while your on it why not add 2 more gpus and 3 more Cells, and wait let Xbox get 4tricore-cpus and 4 Xenos Gpus in total. Oh add 2Gigs of memory to both system instead and make em 256bits wide.

 

[liolio]

Here's a question:

Does anyone really think Xenos would be exactly as it was today if the daughter die wasn't there?

Edit: Go no further, i have some numbers - X800 Xl 512 MB = 160 million Trans / Geforce 6800 GT = 220 Million+ Trans

Thats a 80+ million difference. Wink

They're quite different chips. The one with the larger transistor count is implementing SM3.0 vs SM2.0 for starters.

I'm not comparing Xenos to RSX here at all by the way. I'm wondering what Xenos might have been like if the money spent on the daughter die was spent on Xenos. I'm not saying it would have emerged better or worse overall, but without knowing I prefer "built-in" to "free". That's all, relax.

considering the 22Gb/s to memory are shared by Cpu&Gpu I don't think how the Whole systeme could have been efficient whithout the daughter ship.